1. Field of the Invention:
This device relates to a noise-preventing structure for water mixing cocks, which use a pair of ceramic plate valves. Among sanitary washing machines, such as faucets, the structure is capable of preventing the occurrence of noise and an increase in the internal pressure when a valve is opened suddenly, and improving the operation efficiency thereof.
2. Description of the Prior Art:
There are conventional structures for preventing the occurrence of noise in a valve portion of a water cock using a plate valve, which structures are disclosed in FIGS. 5 and 14 (FIGS. 8a and 8b in the present application) in Japanese Utility Model Publication No. 4298/1982.
These conventional noise-preventing structures will be described briefly with reference to FIGS. 8a and 8b. The structure shown in FIG. 8a has a fluid passage 55 formed in a movable plate valve 54. An elongated net member 56 bent in the shape of the letter "V" is set in a space in the fluid passage 55 by utilizing the resiliency thereof, in such a manner that the net member 56 extends across the fluid passage 55. The structure shown in FIG. 8b also has a net member 56a which is bent in the shape of a butterfly and is set in a fluid passage 55a by utilizing the resiliency thereof.
In these noise-preventing structures, the net member is set in the space in the fluid passage so as to extend across the direction of a flow of a fluid, so that substantially the whole of the extraneous matter contained in the fluid can be collected conveniently. However, when extraneous matter begins to clog the net member, the water, the flow rate and pressure of which are very high even when the valve is opened with the net member in a non-clogged state, flows against the net member with a great impact. Therefore, the resiliency of the net member alone is not able to counteract such a high water pressure; hence, there is the possibility that the net member is readily deformed. When the net member is clogged in a one-sided manner, the flow rate of either the hot water or the cold water is limited greatly. This hampers the smooth valve opening and closing operations, so that the temperature-regulating efficiency decreases to a great extent. In order to remove the extraneous matter from the net member, it is necessary that the portion of the structure which functions as a valve be disassembled. Such a disassembling operation can be done only by a skilled craftsman, and cannot easily be done by an oridinary person in a house.